Traceback (most recent call last):
  File "/usr/bin/image-to-gcode", line 821, in <module>
    main()
  File "/usr/bin/image-to-gcode", line 756, in main
    nim = numpy.fromstring(im.tostring(), dtype=numpy.uint8).reshape((h, w)).astype(numpy.float32)
  File "/usr/lib/python2.7/site-packages/PIL/Image.py", line 712, in tostring
    raise NotImplementedError("tostring() has been removed. "
NotImplementedError: tostring() has been removed. Please call tobytes() instead.